This invention relates generally to carton loading machines and more particularly to a machine for loading an accumulated charge of containers into a carton through an open end on the carton.
Groups of containers are packaged in open top cartons which have a bottom that supports the containers and upstanding flaps therearound to keep the group of containers in the cartons. These open top containers are commonly known as trays. Equipment is available for forming these trays and loading the containers in the tray to package the containers. Typically, this packaging equipment includes a tray handling machine which sets up the tray and positions the tray for loading with the containers, and a tray loading machine which accumulates charges of containers of sufficient size to fill the tray and loads the containers into the tray. In one such arrangement, the tray handling machine sets up the tray for receipt of the charge of containers whereby one set of the end flaps is left open and the thusly set up tray is located in a loading position adjacent the tray loading machine so that the tray loading machine can insert the accumulated charge of containers into the tray through the unclosed end flaps. After the tray has been loaded with the charge of containers, the tray handling machine moves the loaded tray out of the loading position, closes the unclosed end flaps on the tray, and finishes the packaging process such as by applying a heat shrink film about the tray and containers to maintain the package integrity.
In loading the charge of containers into the tray, the tray loading machine typically uses a pusher member to move the charge of containers from the accumulating position into the tray at the loading position. To do this, the pusher member must pass into interference with the unclosed end flaps of the tray. In order for the tray handling machine to move the loaded tray away from the loading position, the pusher member must be retracted out of interference with the unclosed end flaps of the tray.
One such prior art tray loading machine uses a single pusher member to load the containers in the tray. This pusher member is reciprocated back and forth along a linear path between the accumulating and loading positions by a crank arm mechanism such as that shown by U.S. Pat. No. 3,165,871. While such an arrangement does retract the pusher member out of interference with the unclosed end flaps of the loaded tray, it is necessary that the pusher member be extended all the way from the accumulating position to the loading position and retracted all the way from the loading position back past the accumulating position during each loading cycle. This prevented the accumulation of the next charge of containers at the accumulating position until the pusher member had fully reciprocally cycled. In order to achieve reasonable production rates, it was necessary that the pusher member be rapidly reciprocated. As a result, container handling reliability was reduced and wear of machine parts was increased. In order to produce the necessary reciprocatory motion, the drive for the pusher member was complex. As a result, high maintenance costs were associated therewith to keep these machines in operational condition.